Memorial Day Weekend Outbreak 2008

[Bunkertor]

Hint ?

MESOSCALE DISCUSSION 0983
NWS STORM PREDICTION CENTER NORMAN OK
0953 AM CDT FRI MAY 23 2008

AREAS AFFECTED...WRN NEB...FAR NERN CO...NWRN-CNTRL KS

CONCERNING...OUTLOOK UPGRADE

VALID 231453Z - 231600Z

THE UPCOMING 1630Z DAY 1 CONVECTIVE OUTLOOK WILL MAINTAIN THE
PREVIOUS MODERATE RISK AREA ACROSS NWRN-CNTRL KS AND SCNTRL-SWRN
NEB. BUT...THE MODERATE RISK WILL BE EXPANDED WEST AND NORTHWEST TO
INCLUDE FAR NERN CO AND THE ERN PNHDL/NWRN NEB. METEOROLOGICAL
DETAILS WILL BE FORTHCOMING IN THE OUTLOOK UPDATE SHORTLY.

..RACY/HALES.. 05/23/2008


ATTN...WFO...TOP...ICT...GID...LBF...DDC...GLD...BOU...CYS...

37940096 40290310 41760410 42920334 42820163 42200023
40709856 39109791 37779797 37379968

[Tstormwatcher]

Here is a video of the Colorado Tornado. http://www.youtube.com/watch?v=VzDsi5-up-U

[CrazyC83]

It suggests that the risk will remain MDT at 1630Z, but much of the SLGT area will become MDT in the Nebraska Panhandle, NE Colorado and extreme E Wyoming. An upgrade at 2000Z is possible if things get more unstable.

[RL3AO]

So it looks like this will be more of a threat after dark?

[RL3AO]

Storm Survey for Weld County Tornadoes Scheduled for Friday, May 23rd

The NWS will be doing an official storm survey on the front range tornadoes tomorrow May 23rd. Please check our website later for the storm survey results.

[tornado92]

Some storms just beginnning to ignite looking at the radar here. Looks like Nebraska would be hit hard today.

[CrazyC83]

SPC AC 231558

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1058 AM CDT FRI MAY 23 2008

VALID 231630Z - 241200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER MUCH OF NEB INCLUDING THE
PANHANDLE...MUCH OF WESTERN KS AND FAR NERN CO......

...THERE IS A SLGT RISK OF SVR TSTMS FROM WESTERN OK INTO WRN WY AND
SWRN SD......

...A REGIONAL OUTBREAK OF SEVERE STORMS IS ANTICIPATED AGAIN THIS
AFTERNOON AND EVENING OVER PARTS OF NEB/KS...


..SYNOPSIS...
THE INTENSE/COMPLEX WRN U.S. COLD UPPER LOW PERSISTS WITH A GRADUAL
SLOW RETROGRESSION. STRONG JET MAX/SHORT WAVE TROUGH LIFTS NNEWD
FROM NM INTO THE CENTRAL/NRN HIGH PLAINS THIS AFTERNOON/EVENING AS A
100KT PLUS 500 MB WIND MAX DRIVES SSEWD JUST OFF THE CA COAST.

IN RESPONSE TO THE APPROACHING WIND MAX FROM NM...SURFACE LOW
DEEPENS OVER ERN CO TODAY ALLOWING LOW LEVEL MOISTURE TO SPREAD BACK
INTO NERN CO NWD THRU ERN WY/WRN NE ON ELY UPSLOPE FLOW. THE
SCENARIO FROM THE EARLIER OUTLOOK STILL VALID AS HEATING WILL ALLOW
SURFACE BASED DEVELOPMENT OF SUPERCELLS INCLUDING TORNADOES AND VERY
LARGE HAIL ALONG AND E OF THE PRONOUNCED DRY LINE THAT WILL SET UP
FROM SWRN KS NNWWD THRU NERN CO INTO WRN NEB/SERN WY BORDER AREA.

...ERN WY/NERN CO/NEB PANHANDLE...
UPSLOPE FLOW CONTINUES TO TRANSPORT MOISTURE WESTWARD INTO
THE HIGH PLAINS OF NORTHEAST CO/SOUTHEAST WY AND THE NEB PANHANDLE.
MODELS ARE IN GENERAL AGREEMENT THAT DEWPOINTS WILL RISE INTO THE
MID 50S NEB PANHANDLE AND TO NEAR 50 SERN WY. COLD TEMPERATURES
ALOFT AND STEEP LAPSE RATES WILL HELP YIELD SUFFICIENT INSTABILITY
FOR INTENSE STORM DEVELOPMENT BY MID/LATE AFTERNOON. BACKED SURFACE
WINDS AND SIGNIFICANT VEERING/INCREASING WINDS WITH HEIGHT WILL
RESULT IN EFFECTIVE HELICITY VALUES OF 150-250 J/KG AND EFFECTIVE
SHEAR VALUES OF 40-50 KNOTS. THIS WILL PROMOTE SUPERCELLS CAPABLE
OF LARGE HAIL AND A FEW TORNADOES BY MID AFTERNOON. HAVE BROUGHT THE
MDT RISK BACK INTO THE NEB PANHANDLE WHERE AIRMASS WILL BECOME MORE
UNSTABLE THAN EARLIER EXPECTED.

...WRN KS/NEB...
THIS MORNINGS CONVECTION OVER MUCH OF KS AND SOUTHERN NEB WILL
LIKELY LEAVE RESIDUAL OUTFLOW BOUNDARIES OVER PRIMARY THREAT
AREA...BUT MAY ALSO LEAVE CONSIDERABLE CLOUD COVER FOR MUCH OF THE
DAY. MUCH OF MODEL GUIDANCE SUGGESTS CLOUDS WILL BE MAINTAINED
THROUGH AT LEAST MID AFTERNOON ALONG AND NORTH OF I-70 AND THIS IS
SUPPORTED BY CURRENT DATA WITH AN E/W BOUNDARY CURRENTLY S OF
SLN-HYS LINE. NEVERTHELESS...SOUTHEASTERLY LOW LEVEL WINDS CONTINUE
TO DRAW RICH GULF MOISTURE INTO THE REGION WITH AFTERNOON MLCAPE
VALUES OF 1000-1500 J/KG IN CLOUDY AREA...TO 2500-3000 J/KG OVER
SOUTHERN KS. SHORTWAVE RIDGING AND CAPPING WILL ALSO EXIST THROUGH
MUCH OF THE DAYLIGHT HOURS...BEFORE NEXT STRONG SHORTWAVE APPROACHES
TOWARD 00Z. THIS WILL RESULT IN ISOLATED SUPERCELL THUNDERSTORMS
DURING THE AFTERNOON ALONG THE DRYLINE WRN KS ...BECOMING MORE
WIDESPREAD BY EVENING OVER WEST CENTRAL KS AND TRACKING
NORTH-NORTHEASTWARD TOWARD SOUTHERN NEB. FORECAST SOUNDINGS SHOW
IMPRESSIVE LOW LEVEL AND DEEP LAYER VERTICAL SHEAR FAVORABLE FOR
STRONG AND POTENTIALLY LONG-LIVED TORNADOES WELL INTO THE NIGHT.
VERY LARGE HAIL WILL ALSO BE LIKELY IN STRONGER STORMS. IF BOUNDARY
CURRENTLY ANALYZED ALONG THE I-70 CORRIDOR REMAINS INTACT THROUGH
THE AFTERNOON...THIS MAY BE THE AREA OF GREATEST TORNADO THREAT.


...OK/TX...
STRONG INSTABILITY WILL BE PRESENT ALONG SURFACE DRYLINE FROM
WESTERN OK INTO WEST TX TODAY. WEAK LARGE SCALE FORCING IS EXPECTED
TO KEEP CONVECTIVE ACTIVITY EXTREMELY ISOLATED ALONG THIS AXIS.
HOWEVER...ANY STORMS THAT FORM WILL HAVE A THREAT OF LARGE
HAIL...DAMAGING WINDS...AND POSSIBLY TORNADOES. SUFFICIENT CINH
SHOULD LIMIT THE SEVERE THREAT TO ALONG AND JUST E OF THE DRYLINE.

...SRN CA...
VERY UNUSUAL CONDITIONS PERSISTS WRN U.S. AS AN INTENSE CYCLONIC JET
MAX TRACKS SSEWD JUST OFF THE CENTRAL/SRN CA COAST TODAY. LOW LEVEL
CIRCULATION SRN CA COASTAL WATERS WILL MAINTAIN A MOIST ONSHORE
MARINE FLOW THRU THE AFTERNOON WHICH COUPLED WITH THE STEEP LAPSE
RATES AND STRONG CYCLONIC SHEAR SUPPORT DEVELOPMENT OF THUNDERSTORMS
FROM THE COASTAL VALLEYS INLAND TO THE DESERTS. IN ADDITION TO HAIL
THE DEEP LAYER CYCLONIC SHEAR IS SUFFICIENT FOR ROTATING UPDRAFTS
AND POSSIBLE WATERSPOUTS NEAR THE COAST AND A BRIEF ISOLATED TORNADO
OR TWO INLAND.

..HALES/HURLBUT.. 05/23/2008

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
CURRENT UTC TIME: 1620Z (12:20PM), RELOAD THIS PAGE TO UPDATE THE TIME

[Bunkertor]

Some storms just beginnning to ignite looking at the radar here. Looks like Nebraska would be hit hard today.

True - clouds shooting up rapidly

[CrazyC83]

MESOSCALE DISCUSSION 0985
NWS STORM PREDICTION CENTER NORMAN OK
0113 PM CDT FRI MAY 23 2008

AREAS AFFECTED...NERN CO...SERN WY

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 231813Z - 231945Z

MID-LEVEL IMPULSE APPEARS TO BE MOVING NWD OUT OF NM EARLY THIS AFTN
AND IS LIKELY ENHANCING DIURNAL CONVECTION ALONG THE FRONT RANGE NWD
INTO SERN WY. LINE OF TCU HAS ALSO SHARPENED FROM ADAMS COUNTY NEWD
INTO CNTRL MORGAN COUNTY. MESOANALYSIS SHOWS THAT LOW-LEVEL DRY AIR
WAS MIXING QUICKLY NWD INTO ECNTRL CO...BUT MID-UPR 40S TO LWR 50S
DEW POINTS SHOULD SLOSH WWD INTO FAR NERN CO AND SERN WY DURING THE
COURSE OF THE AFTN.

LOW-LEVEL ESELY FLOW COUPLED WITH STRONG SLY H5 FLOW WILL BOOST
VERTICAL SHEAR SUFFICIENT FOR SUPERCELLS. GIVEN THE VERY STEEP
MID-LEVEL LAPSE RATES...LARGE HAIL...SOME VERY LARGE...WILL BE
LIKELY...ESPECIALLY OVER NERN CO. MEANWHILE...TORNADOES WILL ALSO
BE POSSIBLE...PRIMARILY ACROSS NRN/CNTRL WELD...CNTRL/ERN
LARIMER...NRN MORGAN...NRN WASHINGTON AND LOGAN COUNTIES IN CO WHERE
LOW-LEVEL FLOW WILL HAVE THE STRONGEST ELY COMPONENT AMIDST SURGING
MOISTURE.

..RACY.. 05/23/2008


ATTN...WFO...BOU...CYS...

41000595 41350659 41690671 41930641 42160575 42410489
42280445 41800402 41310352 40690322 40200296 40050332
40200379 40160428 40050477 40060507 40270522 40420537
40630559

[RL3AO]

SB Cape

[CrazyC83]

4000 CAPE, no CINH = explosive potential over SW Kansas/NW Oklahoma. With those kind of conditions, a PDS watch is warranted right now...

[RL3AO]

Look at this helicity.

[CrazyC83]

SEL0

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 340
NWS STORM PREDICTION CENTER NORMAN OK
1240 PM MDT FRI MAY 23 2008

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

PARTS OF NORTHEAST COLORADO
MUCH OF NEBRASKA PANHANDLE
PARTS OF EASTERN WYOMING

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 1240 PM UNTIL
700 PM MDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH NORTHEAST OF
DOUGLAS WYOMING TO 25 MILES WEST SOUTHWEST OF AKRON COLORADO.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

DISCUSSION...VERY STRONG VEERING SHEAR PROFILES E OF HIGHER TERRAIN
IN SERN WY/NERN CO WITH INCREASINGLY MOIST SELY FLOW. WITH LITTLE
REMAINING CINH...THUNDERSTORMS EXPECTED TO INCREASE RAPIDLY IN
NUMBER/INTENSITY. SUPERCELLS WILL DEVELOP WITH ASSOCIATED VERY
LARGE HAIL AND POSSIBLE TORNADOES AS THEY MOVE QUICKLY N ACROSS
WATCH AREA.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 18040.


...HALES

[RL3AO]

Just waiting now.

SHORTWAVE RIDGING AND CAPPING WILL ALSO EXIST THROUGH
MUCH OF THE DAYLIGHT HOURS...BEFORE NEXT STRONG SHORTWAVE APPROACHES
TOWARD 00Z. THIS WILL RESULT IN ISOLATED SUPERCELL THUNDERSTORMS
DURING THE AFTERNOON ALONG THE DRYLINE WRN KS ...BECOMING MORE
WIDESPREAD BY EVENING OVER WEST CENTRAL KS AND TRACKING
NORTH-NORTHEASTWARD TOWARD SOUTHERN NEB.

[CrazyC83]

Fortunately, the maximum helicity is not in the area with the extreme CAPE/minimal CINH. (If that was the case, we'd be dealing with Greensburg-like supercells right now)

[Bunkertor]

Look at this helicity.

Insane

So the EHI is around 10.

[RL3AO]

Great looking SVR cell in NW Kansas.

[RL3AO]

Could get a TOR on this Thomas, KS cell pretty quick. Showing signs of developing rotation.

[CrazyC83]

New watch coming, possibly PDS:

MESOSCALE DISCUSSION 0986
NWS STORM PREDICTION CENTER NORMAN OK
0158 PM CDT FRI MAY 23 2008

AREAS AFFECTED...WRN KS

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 231858Z - 232100Z

SWLY LOW-LEVEL DRY FLOW HAS INCREASED SIGNIFICANTLY ALONG THE SRN
HIGH PLAINS AS A SHORTWAVE TROUGH CONTINUES TO TRANSLATE NNEWD
THROUGH NM EARLY THIS AFTN. WOULD EXPECT THAT THE DRYLINE
CIRCULATION WILL BECOME ENHANCED BETWEEN 20-22Z FROM WRN SHERMAN
COUNTY SWD INTO ERN KEARNY...ERN STEVENS COUNTIES AS THE WAVE
GLANCES THE REGION.

RADAR/VSBL SATL SHOWS THAT THE SWWD MOVING OUTFLOW IN NRN/CNTRL KS
WAS BEGINNING TO SLOW AND WILL LIKELY STALL INVOF KGLD SEWD INTO NRN
BARTON COUNTY. WARM SECTOR BETWEEN THE DRY LINE AND THIS BOUNDARY
WILL BECOME STRONGLY UNSTABLE OWING TO IMPRESSIVE LOW/MID-60S SFC
DEW POINTS BENEATH VERY STEEP H7-H5 LAPSE RATES.

TSTM INITIATION IS LIKELY WITHIN THE DRYLINE CIRCULATION BY
21Z...PROBABLY EVOLVING SWD FROM ACTIVITY E OF KGLD. LOW-LEVEL FLOW
SHOULD GENTLY BACK INTO MORE OF A SELY DIRECTION LATER THIS
AFTN...EFFECTIVELY INCREASING LOW-LEVEL SRH ABOVE 200 M2/S2. AT THE
SAME TIME...MORE MERIDIONAL FLOW SHOULD BE CONFINED UPSTREAM OVER
CO...ALLOWING DEEP LAYER SHEAR VECTORS TO MAINTAIN A SUFFICIENT
DEGREE OF NORMAL COMPONENT ACROSS THE DRYLINE FOR DISCRETE STORMS.
GIVEN POTENTIAL FOR DISCRETE STORMS...LOW LCLS AND INCREASING
SRH...TORNADOES WILL BE LIKELY...ESPECIALLY NEAR/N OF KDDC NNEWD
TOWARD HYS/KGBD. BUNKERS SUGGESTS A STORM MOTION OF 190-200 DEGREES
AT 25-30 KTS.

..RACY.. 05/23/2008


ATTN...WFO...DDC...GLD...

37000095 37070123 37370137 37950134 38660140 39030169
39270190 39630152 39360059 38679966 38409936 37889931
37339932 37059931 37049969

[CrazyC83]

SEL1

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 341
NWS STORM PREDICTION CENTER NORMAN OK
215 PM CDT FRI MAY 23 2008

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

PARTS OF EASTERN COLORADO
LARGE PART OF WESTERN KANSAS
PARTS OF SOUTHWESTERN NEBRASKA

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 215 PM UNTIL
1000 PM CDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

DESTRUCTIVE TORNADOES...LARGE HAIL TO 4 INCHES IN DIAMETER...
THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE
POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES EAST NORTHEAST OF
IMPERIAL NEBRASKA TO 40 MILES WEST SOUTHWEST OF MEDICINE LODGE
KANSAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 340...

DISCUSSION...VERY UNSTABLE PER 18Z DDC SOUNDING WITH LITTLE
REMAINING CINH IN WARM SECTOR. E/W SURFACE BOUNDARY WILL FOCUS RAPID
DEVELOPMENT OF TORNADIC SUPERCELLS NEAR INTERSECTION OF N/S DRY LINE
IN WRN KS. WITH VERY STRONG SHEAR POTENTIAL FOR LONG LIVED
SUPERCELLS AND STRONG TORNADOES AS STORMS MOVE RAPIDLY NWD AHEAD OF
APPROACHING UPPER TROUGH/WIND MAX.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 19040.


...HALES